NIS - libdoc.who.int - World Health Organization

WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
caffeoylmalic acid and coptisine, were examined for their activity against
acetylcholine-induced contractions in ileum isolated from rats. Acetylcholine-induced
contractions were slightly reduced by the extract (12.7%;
2 mg/ml), and by coptisine (16.5%; 0.1 mg/ml) (64). In another study, acetylcholine-induced
contractions in isolated guinea-pig ileum were antagonized
by the addition of protopine and allocryptopine (IC 50
2.3 µM) to the
bath media, whereas berberine potentiated the contractions (65).
Choleretic activity
The choleretic activity of an ethanol extract of the herb was assessed in
isolated perfused rat liver. The extract (70% ethanol v/v, 5:1, 1.6% total
alkaloids and 1.9% hydroxycinnamic acid derivatives), as well as separated
alkaloid and phenolic fractions of the extract, increased bile flow. A 70%
ethanol extract of the herb significantly (p < 0.05) increased bile flow by
20% after pretreatment (40 minutes) at a concentration of 10 mg/ml (66).
Central nervous system effects
The effects of a 95% ethanol extract of the herb on the modulation of
γ-aminobutyric acid- (GABA-)activated chloride current in acutely dissociated
periaqueductal grey neurons were investigated using the nystatin-perforated
patch-clamp technique. High concentrations of the extract (150 µg/
ml) elicited an ion current that was blocked by bicuculline. Lower concentrations
of the extract (90 µg/ml) reduced the GABA-activated current
which operates through G-proteins in periaqueductal grey neurons (67).
The effect of a dry ethanol extract (95%) of the herb on the binding of
radiolabelled muscimol to the GABA-A receptor was investigated in the
brain cortex of male rats in vitro. At a concentration of 90 µg/assay, the
extract enhanced [3H]-muscimol-specific binding by 115%, while 160 g/
assay of the extract exerted a 50% inhibition of the specific binding of
[3H]-muscimol. The allosteric modulation of the GABA-A receptor by
the crude extract was due to the presence of protopine. Specific binding of
[3H]-muscimol was inhibited only by sanguinarine and chelerythrine,
with IC 50
values of 25 µM and 39 µM, respectively. However, the concentration
of chelerythrine and sanguinarine in the extract was too low to
account for the observed effect of the extract on [3H]-muscimol binding
to the GABA-A receptor (68).
Antitumour activity
The effects of an extract of the herb on the development of gastric tumours
in rats were assessed after the administration of N-methyl-
N’nitro-N-nitrosoguanidine (MNNG). Sixty-four male 6-week-old
80